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2022-05-23 08:58:02 -0500 received badge  Famous Question (source)
2022-01-23 11:20:08 -0500 commented question laser_filter not working

Do you see anything from rostopic echo scan or rostopic echo base_scan?

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2021-04-09 07:03:59 -0500 marked best answer laser_filters LaserScanRangeFilter not publishing

I'm trying to use the LaserScanRangeFilter to remove points that are far away. However, nothing is published on the topics it should be mapping to.

Here is my laser_filter_config.yaml:

scan_filter_chain:
  - name: range
    type: laser_filters/LaserScanRangeFilter
    params:
      use_message_range_limits: false
      lower_threshold: 0.0
      upper_threshold: 2.0
      lower_replacement_value: -.inf
      upper_replacement_value: .inf

Here is my launch file (I am using the Autonomous Research Kit provided by Clearpath for the Husky robot):

<launch>
  <!-- We want to wait for the ARK to start up, so we don't run right away -->
  <arg name="node_start_delay" default="4.0" />  
  <arg name="route" default="$(dirname)/../config/route.json"/>

  <!-- Start the ARK navigation server -->
  <include file="$(find husky_cpr_ark_navigation)/launch/husky_ark_navigation.launch">
      <arg name="front_laser" value="/front/scan_processed"/>
      <arg name="rear_laser" value="/rear/scan_processed"/>
  </include>

  <node pkg="laser_filters" type="scan_to_scan_filter_chain" output="screen"
      name="laser_filter">
    <rosparam command="load" file="$(dirname)/../config/laser_filter_config.yaml" />
    <remap from="/front/scan" to="/front/scan_processed" />
    <remap from="/rear/scan" to="/rear/scan_processed" />
  </node>
</launch>

I can do rostopic echo /front/scan and rostopic echo /rear/scan and I see the lidars are generating data, but nothing appears when I do rostopoic echo /front/scan_processed or rostopoic echo /rear/scan_processed.

I also looked at rqt_graph and there is nothing going in or out of the laser_filter node.

I would really appreciate any advice.

2021-04-08 17:54:47 -0500 answered a question laser_filters LaserScanRangeFilter not publishing

I was able to figure this out. The issue was I didn't realize how remap worked. This helped a lot. Here is a working la

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2021-04-08 12:09:28 -0500 asked a question laser_filters LaserScanRangeFilter not publishing

laser_filters LaserScanRangeFilter not publishing I'm trying to use the LaserScanRangeFilter to remove points that are f

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2021-02-07 15:17:33 -0500 commented question A compilation of questions regarding sourcing with ROS

@gvdhoorn thanks for the suggestion. I will close this post.

2021-02-07 15:16:48 -0500 edited answer A compilation of questions regarding sourcing with ROS

What does source do? When you "source" something in bash, it will execute each line of the file as is it were typed int

2021-02-07 15:15:48 -0500 commented answer A compilation of questions regarding sourcing with ROS

Sorry, good catch @gvdhoorn. I followed it two sections later with the correct response you provided to my previous ques

2021-02-07 13:08:45 -0500 edited answer A compilation of questions regarding sourcing with ROS

What does source do? When you "source" something in bash, it will execute each line of the file as is it were typed int

2021-02-07 13:02:46 -0500 edited answer A compilation of questions regarding sourcing with ROS

What does source do? When you "source" something in bash, it will execute each line of the file as is it were typed int

2021-02-07 12:58:47 -0500 edited answer A compilation of questions regarding sourcing with ROS

What does source do? When you "source" something in bash, it will execute each line of the file as is it were typed int

2021-02-07 12:56:06 -0500 answered a question A compilation of questions regarding sourcing with ROS

What does source do? When you "source" something in bash, it will execute each line of the file as is it were typed int

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2021-02-07 12:55:53 -0500 asked a question A compilation of questions regarding sourcing with ROS

A compilation of questions regarding sourcing with ROS I've personally struggled a lot to understand sourcing in ROS and

2021-02-07 12:42:18 -0500 commented answer Confusion about ROS sourcing

Got it. Thanks for the help! Found a good answer here. I had read it before, but coming back to it fresh, it made a lot

2021-02-07 12:39:52 -0500 commented answer Confusion about ROS sourcing

Got it. Thanks for the help!

2021-02-07 12:18:22 -0500 commented answer Confusion about ROS sourcing

Thanks so much for clearing that up! As a small follow-up, is there any detriment to sourcing multiple workspaces with -

2021-02-07 12:17:49 -0500 commented answer Confusion about ROS sourcing

Thanks so much for clearing that up! As a small follow-up, is there any detriment to sourcing multiple catkin_ws with --

2021-02-07 12:16:40 -0500 marked best answer Confusion about ROS sourcing

I've read many answers about how ROS sourcing works and I'm a bit confused on a couple things:

Can you source an overlay before building it?

This answer says you can add the following to your .bashrc:

source /opt/ros/indigo/setup.bash
source ~/catkin_ws/devel/setup.bash

However, the ROS2 tutorials say the following:

Before sourcing the overlay (your workspace), it is very important that you open a new terminal, separate from the one where you built the workspace. Sourcing an overlay in the same terminal where you built, or likewise building where an overlay is sourced, may create complex issues.

The first answer results in your overlay always being sourced every time you open a terminal. This contradicts the ROS2 tutorial that says you shouldn't source the overlay before building it.

Why do you need to source both /opt/ros/<distro>/setup.bash and ~/catkin_ws/devel/setup.bash?

I looked at the environment variables with printenv when I sourced both of them vs. just the latter and they were the same. It seems like you only need to source ~/catkin_ws/devel/setup.bash given that you have sourced /opt/ros/<distro>/setup.bash before running catkin_make.

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2021-02-06 15:56:05 -0500 asked a question Confusion about ROS sourcing

Confusion about ROS sourcing I've read many answers about how ROS sourcing works and I'm a bit confused on a couple thin

2021-02-04 16:23:26 -0500 answered a question Connecting to Husky's Hokuyos

This ended up being an issue with using a normal Ubuntu ISO to upgrade the Husky instead of the Clearpath provided ISO.

2021-02-04 10:44:40 -0500 marked best answer Unable to subscribe to topics published by Husky

I'm fairly confident this is a networking issue, but not sure exactly how to fix it. If I publish to a topic myself on the Husky, I can subscribe to it from a client. However, I can't subscribe to topics that the Husky creates during startup. For instance, when ssh'd into the Husky, I can use rostopic hz /imu/data and I see that the data is being published. However, if I do the same on the client, I don't get any information.

On the client (~/.zshrc), I have set the following information:

. /opt/ros/melodic/setup.zsh
export ROS_IP=10.10.10.115
export ROS_MASTER_URI=http://10.10.10.111:11311

On the Husky (~/.bashrc) I have set the following:

. /opt/ros/melodic/setup.bash
export ROS_IP=10.10.10.111

In the Husky's /etc/ros/setup.bash, I have the following:

# Mark location of self so that robot_upstart knows where to find the setup file.
export ROBOT_SETUP=/etc/ros/setup.bash

# Setup robot upstart jobs to use the IP from the network bridge.
# export ROBOT_NETWORK=br0

# Insert extra platform-level environment variables here. The six hashes below are a marker
# for scripts to insert to this file.
######

export LCM_DEFAULT_URL=udpm://239.255.76.67:7667?ttl=5
export HUSKY_IMU_XYZ='0 -0.15 0.065'
export HUSKY_IMU_RPY='3.1415 0 0'
export HUSKY_LASER_ENABLE=1

# Pass through to the main ROS workspace of the system.
source /opt/ros/melodic/setup.bash

# I added this in an attempt to make things work
export ROS_IP=10.10.10.111

source /home/administrator/startup_ws/devel/setup.bash
export HUSKY_LOGITECH=1
export HUSKY_JOY_DEVICE=/dev/input/js0
export HUSKY_GAZEBO_DESCRIPTION=$(rospack find husky_gazebo)/urdf/description.gazebo.xacro

Here are the values of various environment variables:

eric@cpr-mic09:~$ echo $ROBOT_NETWORK

eric@cpr-mic09:~$ echo $ROS_IP
10.10.10.111
eric@cpr-mic09:~$ echo $ROS_HOSTNAME

I would really appreciate any advice. Thank you!

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2021-02-04 10:44:32 -0500 commented answer Unable to subscribe to topics published by Husky

Thank you so much! I added 10.10.10.111 cpr-mic09 to /etc/hosts and now it works perfectly! Sorry I didn't get it from y

2021-02-03 17:42:56 -0500 commented answer Unable to subscribe to topics published by Husky

We use a SSH configuration to connect to the robot (we call it val). Not sure if this could be affecting things: Host v

2021-02-03 17:42:07 -0500 commented answer Unable to subscribe to topics published by Husky

If I run ping cpr-mic09, I get cpr-mic09: Name or service not known, but if I do ping cpr-mic09.local, it works.

2021-02-03 17:34:12 -0500 commented answer Unable to subscribe to topics published by Husky

Sorry, should have tried those and not assumed it was Husky specific. I think I'm falling into the second troubleshootin

2021-02-03 17:12:47 -0500 commented answer Unable to subscribe to topics published by Husky

Thanks for the script! It definitely is a lot cleaner than what I was using, but it's still not working for me. I'm in t

2021-02-03 17:12:37 -0500 commented answer Unable to subscribe to topics published by Husky

Thanks for the script! It definitely is a lot cleaner than what I was using, but it's still not working for me. I'm in t

2021-02-03 14:02:16 -0500 commented answer Unable to subscribe to topics published by Husky

Thanks so much! I'll try this out and hopefully, it fixes the issue

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2021-02-03 10:20:43 -0500 asked a question Unable to subscribe to topics published by Husky

Unable to subscribe to topics published by Husky I'm fairly confident this is a networking issue, but not sure exactly h